The present invention relates to a chain, and more particularly to a coupling portion of a chain.
Chain is widely used as chain transmission in bicycle or motorcycle. A conventional chain is shown in FIGS. 4 and 5 and comprises a plurality pairs of inner sheets I and a plurality pairs of outer sheets O alternatively coupled together. A pair of bushes B are coupled between every pair of inner sheets I. A roller R is rotatably provided on each bush B. A pin P passes each bush B and is fixed between each pair of outer sheets O. Both ends of each pin P extend beyond the outer sheets O. The ends of the pin P are disc shaped so that the sheets I and O are coupled together. The protruded ends of the pins P affect the shifting of the gears of the bicycle which has multispeeds.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional chains.